Modified cas9 protein and use thereof

ABSTRACT

The present invention aims to provide a modified Cas9 protein with relaxed restriction on target sequence while maintaining binding ability to guide RNA, and use thereof. A protein containing the amino acid sequence of SEQ ID NO: 1 in which the 1335-position arginine is mutated into alanine (R1335A), isoleucine (R1335I), methionine (R1335M), threonine (R1335T) or valine (R1335V), the 1111-position leucine is mutated into arginine (L1111R), the 1135-position aspartic acid is mutated into valine (D1135V), the 1218-position glycine is mutated into arginine (G1218R), the 1219-position glutamic acid is mutated into phenylalanine (E1219F), the 1322-position alanine is mutated into arginine (A1322R), and the 1337-position threonine is mutated into arginine (T1337R), and the like.

INCORPORATION-BY-REFERENCE OF MATERIAL ELECTRONICALLY SUBMITTED

Incorporated by reference in its entirety herein is a computer-readablenucleotide/amino acid sequence listing submitted concurrently herewithand identified as follows: 356,311 bytes ASCII (Text) file named“763017SequenceListing.txt,” created May 16, 2022.

TECHNICAL FIELD

The present invention relates to a modified Cas9 protein with anexpanded targetable region, and use thereof.

BACKGROUND ART

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) areknown to compose the adaptive immune system that provides acquiredresistance against invasive foreign nucleic acids in bacteria andarchaea together with Cas (CRISPR-associated) genes. CRISPR frequentlyoriginate from phage or plasmid DNA and are composed of 24 bp to 48 bpshort, conserved repeat sequences having unique variable DNA sequencesreferred to as spacers of similar size inserted there between. Inaddition, a group of genes encoding the Cas protein family is present inthe vicinity of the repeat and spacer sequences.

In the CRISPR-Cas system, foreign DNA is cleaved into fragments of about30 bp by the Cas protein family and inserted into CRISPR. Cas1 and Cas2proteins, which are among the Cas protein family, recognize a basesequence referred to as proto-spacer adjacent motif (PAM) of foreignDNA, cut the upstream, and insert same into the CRISPR sequence of thehost, which creates immune memory of bacteria. RNA generated bytranscription of a CRISPR sequence including immune memory (referred toas pre-crRNA) is paired with a partially complementary RNA(trans-activating crRNA: tracrRNA) and incorporated into Cas9 proteinwhich is one of the Cas protein family. The pre-crRNA and tracrRNAincorporated into Cas9 are cleaved by RNaseIII to form small RNAfragments (CRISPR-RNAs: crRNAs) containing a foreign sequence (guidesequence), and a Cas9-crRNA-tracrRNA complex is thus formed. TheCas9-crRNA-tracrRNA complex binds to a foreign invasive DNAcomplementary to crRNA, and the Cas9 protein, which is an enzyme thatcleaves the DNA (nuclease), cleaves the foreign invasive DNA, therebysuppressing and eliminating the function of the DNA that invaded fromthe outside.

Cas9 protein recognizes the PAM sequence in the foreign invasive DNA,and cleaves the double-stranded DNA at the upstream thereof to give ablunt end. The length and base sequence of the PAM sequence varydepending on the bacterial species, and Streptococcus pyogenes (S.pyogenes) recognizes 3 bases of “NGG”. Streptococcus thermophilus (S.thermophilus) has two Cas9 and they respectively recognize 5-6 bases inthe form of “NGGNG” or “NNAGAA” as PAM sequences. Francisella novicida(F. novicida) recognizes three bases of “NGR”. The number of bpsupstream at which the PAM sequence is cleaved varies depending on thebacterial species. Most Cas9 orthologs, including S. pyogenes, cleave 3bases upstream of the PAM sequence.

In recent years, techniques for applying the CRISPR-Cas system inbacteria to genome editing have been actively developed. crRNA andtracrRNA are fused, expressed as a tracrRNA-crRNA chimera (hereinafterto be referred to as guide RNA: gRNA), and utilized. Using this,nuclease (RNA-guided nuclease: RGN) is then recruited to cleave genomicDNA at the target site.

The CRISPR-Cas system includes types I, II, and III, and type IICRISPR-Cas system is used nearly exclusively for genome editing, andCas9 protein is used as RGN in type II. Since S. pyogenes-derived Cas9protein recognizes three bases of NGG as a PAM sequence, it can becleaved at the upstream as long as there is a sequence havingconsecutive two guanines.

A method using the CRISPR-Cas system only needs to synthesize a shortgRNA homologous to the target DNA sequence, and can perform genomeediting using the Cas9 protein which is a single protein. Therefore, itis not necessary to synthesize large proteins that differ for each DNAsequence in the manner of conventionally used zinc finger nuclease (ZFN)or transcription activator-like effector nuclease (TALEN), and genomeediting can be performed easily and quickly.

Patent Document 1 discloses a genome editing technique that uses aCRISPR-Cas system derived from S. pyogenes.

Patent Document 2 discloses a genome editing technique that uses aCRISPR-Cas system derived from S. thermophilus. Moreover, Patentdocument 2 discloses that a Cas9 protein mutant D31A or N891A functionsas a DNA nicking enzyme, nickase, that places a nick only in one of theDNA strands. Moreover, these mutants are also indicated as havinghomologous recombination efficiency comparable to that of wild-type Cas9protein while retaining a low incidence of non-homologous end-joiningsusceptible to the occurrence of mutations such as insertions, deletionsand the like in the repair mechanism following DNA cleavage.

Non-Patent Document 1 discloses a CRISPR-Cas system that uses S.pyogenes-derived Cas9, wherein the CRISPR-Cas system is a double nickasesystem that uses two Cas9 protein D10A mutants and a pair oftarget-specific guide RNA that form a complex with these D10A mutants.Each complex of Cas9 protein D10A mutant and target-specific guide RNAcreates only one nick in DNA strand homologous to the guide DNA. Thepair of guide RNA has about 20 bases of mismatch and only recognizes atarget sequence located in the opposite strand of the target DNA. Thetwo nicks created by each complex of Cas9 protein D10A mutant andtarget-specific guide RNA mimic a DNA double-strand break (DSB), and theuse of the pair of guide RNA is indicated as being able to improve thespecificity of Cas 9 protein-mediated genome editing while maintaining ahigh level of efficiency.

Patent document 3 discloses various Cas9 protein mutants derived from S.pyogenes and Patent Document 4 discloses various Cas9 protein mutantsderived from F. novicida.

DOCUMENT LIST Patent Documents

-   patent document 1: WO2014/093661-   patent document 2: National Publication of International Patent    Application No. 2015-510778-   patent document 3: WO2016/141224-   patent document 4: WO2017/010543

Non-Patent Document

-   non-patent document 1: Ran, F. A., et al., Double Nicking by    RNA-Guided CRISPR Cas9 for Enhanced Genome Editing Specificity,    Cell, vol. 154, p 1380-1389, 2013.

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The PAM sequence able to be recognized by the S. pyogenes-derived Cas9(to be also referred to as SpCas9 in the present specification) proteindisclosed in patent document 1 consists of two bases of “NGG (N is anybase)”. In addition, the double nickase system disclosed in non-patentdocument 1 uses SpCas9 protein, and since recognizable PAM sequences arerequired at a total of two locations in the sense strand and antisensestrand within a target sequence, there are further limitations on thosetarget sequences that are able to be edited.

Since there are limitations on the PAM sequences that conventional Cas9proteins can recognize, there is also a problem of limitation on theeditable target sequences.

The present invention aims to provide a modified Cas9 protein withrelaxed restriction on target sequence while maintaining binding abilityto guide RNA, and use thereof.

Means of Solving the Problems

The present inventors have taken note of SpCas9 protein as Cas9 protein,and conducted intensive studies in an attempt to solve theabove-mentioned problems. As a result, they have succeeded in convertinga PAM sequence conventionally consisting of 2 bases of NGG (N is anybase) to a 1 base sequence of NG while maintaining the binding abilityto guide RNA, by substituting an amino acid at a predetermined positionof the SpCas9 protein with a specific amino acid (introducing amutation), which resulted in the completion of the present invention.

In the present specification, Cas9 protein before introduction ofmutation is sometimes to be referred to as wild-type Cas9 protein, andCas9 protein after introduction of mutation is sometimes to be referredto as modified Cas9 protein or mutant Cas9 protein.

That is, the present invention provides the following.

[1] A protein consisting of a sequence comprising the amino acidsequence shown in SEQ ID NO: 1 in which the 1335-position arginine issubstituted by one amino acid selected from the group consisting ofalanine, glycine, cysteine, isoleucine, leucine, methionine,phenylalanine, proline, valine, threonine, asparagine and aspartic acid,and having a binding ability to guide RNA.[2] The protein of the above-mentioned [1], further having a mutation atthe 1219-position of the amino acid sequence shown in SEQ ID NO: 1.[3] The protein of the above-mentioned [1] or [2], further having amutation at the 1322-position of the amino acid sequence shown in SEQ IDNO: 1.[4] A protein consisting of a sequence comprising the amino acidsequence shown in SEQ ID NO: 1 in which the 1335-position arginine issubstituted by one amino acid selected from the group consisting ofalanine, glycine, cysteine, isoleucine, leucine, methionine,phenylalanine, proline, valine, threonine, asparagine and aspartic acid,and the 1219-position is further mutated, and having a binding abilityto guide RNA.[5] A protein consisting of a sequence comprising the amino acidsequence shown in SEQ ID NO: 1 in which the 1335-position arginine issubstituted by one amino acid selected from the group consisting ofalanine, glycine, cysteine, isoleucine, leucine, methionine,phenylalanine, proline, valine, threonine, asparagine and aspartic acid,and the 1322-position is further mutated, and having a binding abilityto guide RNA.[6] The protein of any of the above-mentioned [1] to [5], wherein the1335-position arginine is substituted with alanine.[7] The protein of any of the above-mentioned [1] to [5], wherein the1335-position arginine is substituted with isoleucine, methionine,threonine or valine.[8] The protein of the above-mentioned [2] or [4], wherein the mutationat 1219-position is a substitution of glutamic acid to phenylalanine.[9] The protein of the above-mentioned [3] or [5], wherein the mutationat 1322-position is a substitution of alanine to arginine, histidine orlysine.[10] The protein of the above-mentioned [9], wherein the mutation at1322-position is a substitution of alanine to arginine.[11] The protein of any of the above-mentioned [1] to [10], wherein theamino acid sequence shown in SEQ ID NO: 1 has further mutation at atleast one position selected from the group consisting of the1111-position, the 1135-position, the 1218-position and the1337-position.[12] The protein of the above-mentioned [11], wherein the amino acidsequence shown in SEQ ID NO: 1 has further mutation at at least twopositions selected from the group consisting of the 1111-position, the1135-position, the 1218-position and the 1337-position.[13] The protein of the above-mentioned [11], wherein the amino acidsequence shown in SEQ ID NO: 1 has further mutation at at least threepositions selected from the group consisting of the 1111-position, the1135-position, the 1218-position and the 1337-position.[14] The protein of the above-mentioned [11], wherein the amino acidsequence shown in SEQ ID NO: 1 has further mutation at the1111-position, the 1135-position, the 1218-position and the1337-position.[15] The protein of any of the above-mentioned [11] to [14], wherein themutation at 1111-position is a substitution of leucine to arginine,histidine or lysine;

the mutation at 1135-position is a substitution of aspartic acid tovaline;

the mutation at 1218-position is a substitution of glycine to arginine,histidine or lysine; and

the mutation at 1337-position is a substitution of threonine toarginine, histidine or lysine.

[16] The protein of any of the above-mentioned [1] to [15], wherein theSEQ ID NO: 1 has identity of 80% or more at a site other than themutated position(s).[17] The protein of any of the above-mentioned [1] to [15], wherein theSEQ ID NO: 1 comprises one to several amino acids substituted, deleted,inserted and/or added at a site other than the mutated position(s).[18] The protein of any of the above-mentioned [1] to [17], which hasRNA-guided DNA endonuclease activity.[19] The protein of any of the above-mentioned [1] to [16], wherein theamino acid sequence shown in SEQ ID NO: 1 further has a mutation thatpartly or entirely deletes nuclease activity.[20] The protein of any of the above-mentioned [19], wherein themutation that partly or entirely deletes nuclease activity is a mutationat, in the amino acid sequence shown in SEQ ID NO: 1, at least one siteselected from the group consisting of (i) the 10-position, the762-position, the 839-position, the 983-position and the 986-position ora position corresponding thereto, and/or (ii) a site selected from thegroup consisting of the 840-position and the 863-position or a positioncorresponding thereto.[21] The protein of any of the above-mentioned [20], wherein the10-position aspartic acid is substituted by alanine or asparagine; or

the 840-position histidine is substituted by alanine, asparagine ortyrosine.

[22] The protein of any of the above-mentioned [19] to [21], wherein atranscriptional regulator protein or domain is linked.[23] The protein of the above-mentioned [22], wherein thetranscriptional regulator is a transcription activation factor.[24] The protein of the above-mentioned [22], wherein thetranscriptional regulator is a transcription silencer or a transcriptioninhibitory factor.[25] A nucleic acid encoding a protein of any of the above-mentioned [1]to [24].[26] A protein-RNA complex provided with the protein of any of theabove-mentioned [1] to [24] and a polynucleotide composed of a basesequence complementary to a base sequence located 1 to 20 to 24 basesupstream from a proto-spacer adjacent motif (PAM) sequence in a targetdouble-stranded polynucleotide.[27] A method for site-specifically modifying a target double-strandedpolynucleotide, including:

a step for mixing and incubating a target double-strandedpolynucleotide, a protein and a guide RNA, and

a step for having the aforementioned protein modify the aforementionedtarget double-stranded polynucleotide at a binding site located upstreamof a PAM sequence; wherein,

the aforementioned target double-stranded polynucleotide has a PAMsequence composed of NG (wherein, N represents any base and G representsguanine),

the aforementioned protein is the protein of any of the above-mentioned[1] to [24], and

the aforementioned guide RNA contains a polynucleotide composed of abase sequence complementary to a base sequence located 1 to 20 to 24bases upstream from the aforementioned PAM sequence in theaforementioned target double-stranded polynucleotide.

[28] The method of the above-mentioned [27], wherein the modification issite specific cleavage in the target double-stranded polynucleotide.[29] The method of the above-mentioned [27], wherein the modification issite specific substitution, deletion and/or addition of one or morenucleotides in the target double-stranded polynucleotide.[30] A method for increasing expression of a target gene in a cell,comprising expressing the protein of the above-mentioned

and one or multiple guide RNAs for the aforementioned target gene in theaforementioned cell.

[31] A method for decreasing expression of a target gene in a cell,comprising expressing the protein of the above-mentioned [24] and one ormultiple guide RNAs for the aforementioned target gene in theaforementioned cell.[32] The method of the above-mentioned [30] or [31], wherein the cell isa eukaryotic cell.[33] The method of the above-mentioned [30] or [31], wherein the cell isa yeast cell, a plant cell or an animal cell.

Effect of the Invention

According to the present invention, a Cas9 protein can be obtained thatrecognizes a wide range of PAM sequences while retaining bindingstrength with a guide RNA. In addition, a simple and rapid site-specificgenome editing technology for a target sequence can be provided thatuses the aforementioned Cas9 protein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows an image representing the results of agarose gelelectrophoresis in a DNA cleavage activity measurement test inExample 1. “TGT” was used as the PAM sequence and EcoRI was used as therestriction enzyme.

FIG. 1B shows an image representing the results of agarose gelelectrophoresis in a DNA cleavage activity measurement test inExample 1. “TGG” was used as the PAM sequence and HindIII was used asthe restriction enzyme.

FIG. 1C shows an image representing the results of agarose gelelectrophoresis in a DNA cleavage activity measurement test inExample 1. “TGNA” was used as the PAM sequence and BamHI was used as therestriction enzyme.

FIG. 1D shows an image representing the results of agarose gelelectrophoresis in a DNA cleavage activity measurement test inExample 1. “TGN” was used as the PAM sequence and BamHI was used as therestriction enzyme.

FIG. 2 shows an image representing the results of agarose gelelectrophoresis in a DNA cleavage activity measurement test in Example2.

FIG. 3 shows a graph showing the results of a DNA cleavage activitymeasurement test in Example 3. “TGA” was used as the PAM sequence andBamHI was used as the restriction enzyme.

FIG. 4 is a graph showing the results of the DNA cleavage activitymeasurement test in Example 4.

FIG. 5 is a graph showing the results of the DNA cleavage activitymeasurement test in Example 5.

DESCRIPTION OF EMBODIMENTS

The present invention is described below. Unless particularly indicated,the terms used in the present specification have meanings generally usedin the pertinent so field.

<Cas9 Protein Recognizing Wide Range of PAM Sequences>

The protein of the present embodiment is a Cas9 protein that recognizesa wide range of PAM sequences while retaining binding strength with aguide RNA. According to the protein of the present embodiment, a simpleand rapid technique can be provided for site-specific editing of thegenome of a target sequence.

In the present description, “guide RNA” refers to that which mimics thehairpin structure of tracrRNA-crRNA, and contains in the 5′-terminalregion thereof a polynucleotide composed of a base sequencecomplementary to a base sequence located from 1 to preferably 20 to 24bases, and more preferably from 1 to preferably 22 to 24 bases, upstreamfrom the PAM sequence in a target double-stranded polynucleotide.Moreover, guide RNA may contain one or more polynucleotides composed ofa base sequence allowing the obtaining of a hairpin structure composedof base sequences non-complementary to a target double-strandedpolynucleotide symmetrically arranged so as to form a complementarysequence having a single point as the axis thereof.

The guide RNA has a function of binding to the mutant Cas9 protein ofthe present invention and leading the protein to a target DNA. The guideRNA has a sequence at the 5′-terminal which is complementary to thetarget DNA, and binds to the target DNA via the complementary sequence,thereby leading the mutant Cas9 protein of the present invention to thetarget DNA. When the mutant Cas9 protein functions as a DNAendonuclease, the DNA can be cleaved at the site where the target DNAexists and, for example, the function of the target DNA can bespecifically lost.

The guide RNA is designed and prepared based on the sequence informationof the target DNA to be cleaved or modified. Specific examples includesequences such as those used in the Examples.

In the present description, an “endonuclease” refers to an enzyme thatcleaves a nucleotide strand at an intermediate location. Accordingly,the Cas9 protein of the present embodiment that recognizes a wide rangeof PAM sequences and has endonuclease activity has enzyme activityguided by guide RNA that cleaves at an intermediate location of a DNAstrand.

In the present description, the terms “polypeptide”, “peptide” and“protein” refer to polymers of amino acid residues and are usedinterchangeably. In addition, these terms also refer to amino acidpolymers in which one or a plurality of amino acid residues are in theform of a chemical analog or modified derivative of the correspondingamino acids present in nature.

In the present description, a “sequence” refers to a nucleotide sequenceof an arbitrary length, is a deoxyribonucleotide or ribonucleotide, andmay be linear or branched and single-stranded or double-stranded.

In the present description, a “PAM sequence” refers to a sequencepresent in a target double-stranded polynucleotide that can berecognized by Cas9 protein, and the length and base sequence of the PAMsequence differs according to the bacterial species. A sequence capableof being recognized by the Cas9 protein of the present embodimentcapable of recognizing a wide range of PAM sequences can be representedby “5′-NG-3′”.

Furthermore, in the present description, “N” refers to any one baseselected from the group consisting of adenine, cytosine, thymine andguanine, “A” refers to adenine, “G” to guanine, “C” to cytosine, “T” tothymine, “R” to a base having a purine skeleton (adenine or guanine),and “Y” to a base having a pyrimidine skeleton (cytosine or thymine).

In the present description, a “polynucleotide” refers to adeoxyribonucleotide or ribonucleotide polymer having linear or cycliccoordination and may be single-stranded or double-stranded, and shouldnot be interpreted as being restricted with respect to polymer length.In addition, polynucleotides include known analogs ofnaturally-occurring nucleotides as well as nucleotides in which at leastone of the base moieties, sugar moieties and phosphate moieties thereofhas been modified (such as a phosphorothioate backbone). In general, ananalog of a specific nucleotide has the same base-pairing specificity,and for example, A analogs form base pairs with T.

In one embodiment, the present invention provides a protein(embodiment 1) consisting of an amino acid sequence having a mutation atthe 1335-position in the amino acid sequence shown in SEQ ID NO: 1 andhaving a binding ability to guide RNA. In addition, the protein ofembodiment 1 has RNA-guided DNA endonuclease activity.

SEQ ID NO: 1 is a full-length amino acid sequence of SpCas9 protein. Thesequence of the PAM sequence recognition site in the SpCas9 protein isan amino acid sequence consisting of 271 residues from the 1097th to the1368th of SEQ ID NO: 1.

The mutation at the 1335-position of SEQ ID NO: 1 is specificallysubstitution of the 1335-position arginine with one amino acid selectedfrom the group consisting of alanine, glycine, cysteine, isoleucine,leucine, methionine, phenylalanine, proline, threonine, valine,asparagine and aspartic acid. It is preferably substitution withalanine. Another preferred mutation at the 1335-position is substitutionwith isoleucine, methionine, threonine or valine.

By the mutation at the 1335-position, a wider range of PAM sequence ofthe protein can be recognized since hydrogen bonding with the guanine atthe third position in the PAM sequence (5′-NG[G]-3′) no longer exists.

In another embodiment of the present invention, the present inventionprovides a protein further having a mutation at the 1219-position andhaving binding ability to guide RNA (embodiment 2) in addition to themutation of the aforementioned embodiment 1. In addition, the protein ofembodiment 2 has RNA-guided DNA endonuclease activity.

The mutation at the 1219-position is specifically substitution of the1219-position glutamic acid with phenylalanine.

The mutation at the 1219-position can contribute to increase(maintenance) of the expression rate of the RNA-guided DNA endonucleaseactivity.

In another embodiment of the present invention, the present inventionprovides a protein further having a mutation at the 1322-position andhaving binding ability to guide RNA (embodiment 3) in addition to themutation of the aforementioned embodiment 1 or 2.

The mutation at the 1322-position is specifically substitution of the1322-position alanine with arginine, histidine or lysine. It ispreferably substitution with arginine.

The mutation at the 1322-position can contribute to enhancement(activity maintenance) of the activity of the RNA-guided DNAendonuclease activity.

In another embodiment of the present invention, the present inventionprovides a protein having a mutation at at least one, preferably 2, morepreferably 3, selected from the group consisting of the 1111-position,the 1135-position, the 1218-position and the 1337-position, particularlypreferably all 4 positions, and having binding ability to guide RNA(embodiment 4) in addition to the mutation of the aforementionedembodiment 1, 2 or 3. The protein of embodiment 4 has RNA-guided DNAendonuclease activity.

The mutation at the 1111-position is specifically substitution of the1111-position leucine with arginine, histidine or lysine. It ispreferably substitution with arginine.

The mutation at the 1135-position is specifically substitution of the1135-position aspartic acid with valine.

The mutation at the 1218-position is specifically substitution of the1218-position glycine with arginine, histidine or lysine. It ispreferably substitution with arginine.

The mutation at the 1337-position is specifically substitution of the1337-position threonine with arginine, histidine or lysine. It ispreferably substitution with arginine.

In another embodiment of the present invention, the present inventionprovides a protein having a mutation at (i) at least one site selectedfrom the group consisting of (i) the 10-position, the 762-position, the839-position, the 983-position and the 986-position, and/or (ii) a siteselected from the group consisting of the 840-position and the863-position, and having binding ability to guide (embodiment 5).

The mutation at the 10-position is specifically substitution of the10-position aspartic acid with alanine or asparagine.

The mutation at the 762-position is specifically substitution of the762-position glutamic acid with glutamine.

The mutation at the 839-position is specifically substitution of the839-position aspartic acid with alanine or asparagine.

The mutation at the 983-position is specifically substitution of the983-position histidine with asparagine or tyrosine.

The mutation at the 986-position is specifically substitution of the986-position aspartic acid with asparagine.

The mutation at 840-position is specifically substitution of the840-position histidine with alanine, asparagine or tyrosine.

The mutation at the 863-position is specifically substitution of the863-position asparagine with aspartic acid, serine or histidine.

Preferred as embodiment 5 is a protein in which the 10-position asparticacid is substituted with alanine or asparagine, or the 840-positionhistidine is substituted with alanine, asparagine or tyrosine.

A protein of embodiment 5 having mutation of (i) or mutation of (ii) hasnickase activity.

A protein of embodiment 5 having mutation of (i) and mutation of (ii)binds to guide RNA and leaded to target DNA but the endonucleaseactivity is inactivated.

In another embodiment of the present invention, the present inventionprovides a protein (embodiment 6) that is functionally equivalent to theproteins of the aforementioned embodiments 1-5. To be functionallyequivalent to the proteins of the aforementioned embodiments 1-5, theamino acid sequence shown in SEQ ID NO: 1 has identity of 80% or more ata site other than the position(s) where the mutation(s) has(have) beenapplied in the aforementioned embodiments 1-5 and has a binding abilityto guide RNA. When amino acids are increased or decreased due tomutation, the “site other than the position(s) where the mutation(s)has(have) been applied” can be interpreted to mean a “site other thanthe position(s) corresponding to the position(s) where the mutation(s)has(have) been applied”. This identity is preferably 80% or more, morepreferably 85% or more, even more preferably 90% or more, particularlypreferably 95% or more, and most preferably 99% or more. The amino acidsequence identity can be determined by a method known per se. Forexample, amino acid sequence identity (%) can be determined using aprogram conventionally used in the pertinent field (e.g., BLAST, FASTA,etc.) by default. In another aspect, identity (%) is determined by anyalgorithm known in the pertinent field, such as algorithms of Needlemanet al. (1970) (J. Mol. Biol. 48: 444-453), Myers and Miller (CABIOS,1988, 4: 11-17) and the like. The algorithm of Needleman et al. isincorporated into the GAP program in the GCG software package (availableat gcg.com) and the identity (%) can be determined using, for example,any of BLOSUM 62 matrix and PAM250 matrix, as well as gap weight: 16,14, 12, 10, 8, 6 or 4, and length weight: 1, 2, 3, 4, 5 or 6. Thealgorithm of Myers and Miller is incorporated into the ALIGN programthat is a part of the GCG sequence alignment software package. When theALIGN program is used to compare amino acid sequences, for example,PAM120 weight residue table, gap length penalty 12, and gap penalty 4can be used.

As a protein functionally equivalent to the proteins of theaforementioned embodiments 1-5, a protein having the amino acid sequenceshown in SEQ ID NO: 1 in which one to several amino acids aresubstituted, deleted, inserted and/or added at a site other than theposition where the mutations of the aforementioned embodiment 1-5 havebeen applied and having the binding ability to guide RNA (embodiment 7)is provided. When amino acids are increased or decreased due tomutation, the “site other than the position(s) where the mutation(s)have been applied” can be interpreted to mean a “site other than theposition(s) corresponding to the position(s) where the mutation(s) havebeen applied”.

As a technique for artificially performing “substitution, deletion,insertion and/or addition of amino acid”, for example, a methodincluding applying conventional site specific mutation introduction toDNA encoding a predetermined amino acid sequence, and thereafterexpressing the DNA by a conventional method can be mentioned. Examplesof the site specific mutation introduction method include a method usingamber mutation (gapped duplex method, Nucleic Acids Res., 12, 9441-9456(1984)), a PCR method using a mutation introduction primer and the like.

The number of the amino acids modified above is at least one residue,specifically one or several, or more than that. Among the aforementionedsubstitution, deletion, insertion and addition, substitution of aminoacid is particularly preferred. The substitution is more preferablysubstitution with an amino acid having similar properties such ashydrophobicity, charge, pK, and characteristic of steric structure andthe like. Examples of the substitution include substitution within thegroups of i) glycine, alanine; ii) valine, isoleucine, leucine; iii)aspartic acid, glutamic acid, asparagine, glutamine; iv) serine,threonine; v) lysine, arginine; vi) phenylalanine, tyrosine.

As the Cas9 protein that recognizes a wide range of PAM sequences of thepresent invention, preferably, a protein having the amino acid sequence(SEQ ID NO: 18) which is SEQ ID NO: 1 in which the 1335-positionarginine is mutated into alanine (R1335A), the 1111-position leucine ismutated into arginine (L1111R), the 1135-position aspartic acid ismutated into valine (D1135V), the 1218-position glycine is mutated intoarginine (G1218R), the 1219-position glutamic acid is mutated intophenylalanine (E1219F), the 1322-position alanine is mutated intoarginine (A1322R), and the 1337-position threonine is mutated intoarginine (T1337R) can be mentioned.

A protein containing the amino acid sequence of SEQ ID NO: 1 in whichthe 1335-position arginine is mutated into isoleucine (R1335I),methionine (R1335M), threonine (R1335T) or valine (R1335V) (morepreferably R1335M and R1335V), the 1111-position leucine is mutated intoarginine (L1111R), the 1135-position aspartic acid is mutated intovaline (D1135V), the 1218-position glycine is mutated into arginine(G1218R), the 1219-position glutamic acid is mutated into phenylalanine(E1219F), the 1322-position alanine is mutated into arginine (A1322R),and the 1337-position threonine is mutated into arginine (T1337R) isalso preferable as the Cas9 protein that recognizes a wide range of PAMsequences of the present invention. The protein corresponds to a proteincontaining the amino acid sequence of SEQ ID NO: 18 in which the1335-position alanine is respectively mutated into isoleucine,methionine, threonine or valine.

In this specification, the alphabet displayed on the left side of thenumber indicating the number of amino acid so residues up to thesubstitution site indicates a single letter code of the amino acidbefore substitution, and the alphabet displayed on the right sideindicates a single letter code of the amino acid after substitution.

The Cas9 protein recognizing a wide range of PAM sequences in thepresent embodiment can be produced according to, for example, the methodindicated below. First, a host is transformed using a vector containinga nucleic acid that encodes the aforementioned Cas9 protein recognizinga wide range of PAM sequences. Then, the host is cultured to express theaforementioned protein. Conditions such as medium composition, culturetemperature, duration of culturing or addition of inducing agents can bedetermined by a person with ordinary skill in the art in accordance withknown methods so that the transformant grows and the aforementionedprotein is efficiently produced. In addition, in the case of havingincorporated a selection marker in the form of an antibiotic resistancegene in an expression vector, the transformant can be selected by addingantibiotic to the medium. Then, Cas9 protein recognizing a wide range ofPAM sequences is obtained by purifying the aforementioned proteinexpressed by the host according to a method known per se.

There are no particular limitations on the host, and examples thereofinclude animal cells, plant cells, insect cells and microorganisms suchas Escherichia coli, Bacillus subtilis or yeast.

<Complex of Cas9 Protein Recognizing Wide Range of PMA Sequences andGuide RNA>

In one embodiment thereof, the present invention provides a protein-RNAcomplex provided with the protein indicated in the previous section on<Cas9 Protein Recognizing Wide Range of PMA Sequences> and guide RNAcontaining a polynucleotide composed of a base sequence complementary toa base sequence located 1 to 20 to 24 bases upstream from a proto-spaceradjacent motif (PAM) sequence in a target double-strandedpolynucleotide.

According to the protein-RNA complex of the present embodiment, a widerange of PMA sequences can be recognized and a target double-strandedpolynucleotide can be easily and rapidly edited site-specifically for atarget sequence.

The aforementioned protein and the aforementioned guide RNA are able toform a protein-RNA complex by mixing in vitro and in vivo under mildconditions. Mild conditions refer to a temperature and pH of a degreethat does not cause protein decomposition or denaturation, and thetemperature is preferably 4° C. to 40° C., while the pH is preferably 4to 10.

In addition, the duration of mixing and incubating the aforementionedprotein and the aforementioned guide RNA is preferably 0.5 hours to 1hour. The complex formed by the aforementioned protein and theaforementioned guide RNA is stable and is able to maintain stabilityeven if allowed to stand for several hours at room temperature.

<CRISPR-Cas Vector System>

In one embodiment thereof, the present invention provides a CRISPR-Casvector system provided with a first vector containing a gene encoding aprotein indicated in the previous section on <Cas9 Protein RecognizingWide Range of PAM Sequences>, and a second vector containing a guide RNAcontaining a polynucleotide composed of a base sequence complementary toa base sequence located 1 to 20 to 24 bases upstream from PAM sequencein a target double-stranded polynucleotide.

According to the CRISPR-Cas vector system of the present embodiment, awide range of PMA sequences can be recognized and a targetdouble-stranded polynucleotide can be easily and rapidly editedsite-specifically for a target sequence.

The guide RNA is suitably designed to contain in the 5′-terminal regionthereof a polynucleotide composed of a base sequence complementary to abase sequence located from 1 to 20 to 24 bases, and preferably to 22 to24 bases, upstream from a PAM sequence in a target double-strandedpolynucleotide. Moreover, the guide RNA may also contain one or morepolynucleotides composed of a base sequence allowing the obtaining of ahairpin structure composed of base sequences non-complementary to atarget double-stranded polynucleotide symmetrically arranged so as toform a complementary sequence having a single point as the axis thereof.

The vector of the present embodiment is preferably an expression vector.There are no particular limitations on the expression vector, andexamples thereof that can be used include E. coli-derived plasmids suchas pBR322, pBR325, puC12 or puC13; B. subtilis-derived plasmids such aspUB110, pTP5 or pC194; yeast-derived plasmids such as pSH15;bacteriophages such as phages; viruses such as adenovirus,adeno-associated virus, lentivirus, vaccinia virus or baculovirus; andmodified vectors thereof.

In the aforementioned expression vector, there are no particularlimitations on the promoters for expression of the aforementioned Cas9protein or the aforementioned guide RNA, and examples thereof that canbe used include promoters for expression in animal cells such as EF1αpromoter, SRα promoter, SV40 promoter, LTR promoter, cytomegalovirus(CMV) promoter or HSV-tk promoter, promoters for expression in plantcells such as the 35S promoter of cauliflower mosaic virus (CaMV) orrubber elongation factor (REF) promoter, and promoters for expression ininsect cells such as polyhedrin promoter or p10 promoter. Thesepromoters can be suitably selected according to the aforementioned Cas9protein and the aforementioned guide RNA, or the type of cellsexpressing the aforementioned Cas9 protein and the aforementioned guideRNA.

The aforementioned expression vector may also further have amulti-cloning site, enhancer, splicing signal, polyadenylation signal,selection marker or replication origin and the like.

<Method for Site-Specifically Modifying Target Double-StrandedPolynucleotide> First Embodiment

In one embodiment thereof, the present invention provides a method forsite-specifically modifying a target double-stranded polynucleotide,provided with:

a step for mixing and incubating a target double-strandedpolynucleotide, a protein and a guide RNA, and

a step for having the aforementioned protein modify the aforementionedtarget double-stranded polynucleotide at a binding site located upstreamof a PAM sequence; wherein,

the aforementioned target double-stranded polynucleotide has a PAMsequence composed of NG (wherein, N represents any base and G representsguanine),

the aforementioned protein is the protein indicated in theabove-mentioned <Cas9 Protein Recognizing Wide Range of PMA Sequences>,and

the aforementioned guide RNA contains a polynucleotide composed of abase sequence complementary to a base sequence located 1 to 20 to 24bases upstream from the aforementioned PAM sequence in theaforementioned target double-stranded polynucleotide.

According to the method of the present embodiment, a targetdouble-stranded polynucleotide can be modified easily, rapidly andsite-specifically for a target sequence by using mutant Cas9 proteinrecognizing a wide range of PAM sequences.

In the present embodiment, there are no particular limitations on thetarget double-stranded polynucleotide provided it has a PAM sequencecomposed of NG (wherein, N represents any base and G representsguanine).

In the present embodiment, the protein and guide RNA are as indicated inthe previous section on <Cas9 Protein Recognizing Wide Range of PMASequences>.

The following provides a detailed explanation of the method forsite-specifically modifying a target double-stranded polynucleotide.

First, the aforementioned protein and the aforementioned guide RNA aremixed and incubated under mild conditions. Mild conditions are aspreviously described. The incubation time is preferably 0.5 hours to 1hour. A complex formed by the aforementioned protein and theaforementioned guide RNA is stable and is able to maintain stabilityeven if allowed to stand for several hours at room temperature.

Next, the aforementioned protein and the aforementioned guide RNA form acomplex on the aforementioned target double-stranded polynucleotide. Theaforementioned protein recognizes PAM sequences composed of “5′-NG-3′”,and binds to the aforementioned target double-stranded polynucleotide ata binding site located upstream of the PAM sequence. When theaforementioned protein has an endonuclease activity, the polynucleotideis cleaved at this site. As a result of the Cas9 protein recognizing thePAM sequence, and the double helix structure of the targetdouble-stranded polynucleotide being pulled apart starting at the PAMsequence and annealing with a base sequence complementary to the targetdouble-stranded polynucleotide in the guide RNA, the double helixstructure of the target double-stranded polynucleotide is partiallyunraveled. At this time, the aforementioned Cas9 protein cleavesphosphate diester bonds of the target double-stranded polynucleotide ata cleavage site located upstream of the PAM sequence and a cleavage sitelocated upstream of a sequence complementary to the PAM sequence.

Second Embodiment

In the present embodiment, an expression step may be further providedprior to the incubation step in which the protein indicated in theprevious section on <Cas9 Protein Recognizing Wide Range of PAMSequences> and guide RNA are expressed using the previously describedCRISPR-Cas vector system.

In the expression step of the present embodiment, Cas9 protein and guideRNA are first expressed using the aforementioned CRISPR-Cas vectorsystem. A specific expression method consists of transforming a hostusing an expression vector containing a gene that encodes Cas9 proteinand an expression vector containing guide RNA, respectively. Then, thehost is cultured to express the Cas9 protein and guide RNA. Conditionssuch as medium composition, culture temperature, duration of culturingor addition of inducing agents can be determined by a person withordinary skill in the art in accordance with known methods so that thetransformant grows and the aforementioned protein is efficientlyproduced. In addition, in the case of having incorporated a selectionmarker in the form of an antibiotic resistance gene in the expressionvector, the transformant can be selected by adding antibiotic to themedium. Then, the Cas9 protein and guide RNA are obtained by purifyingthe Cas9 protein and guide RNA expressed by the host according to asuitable method.

<Method for Site-Specifically Modifying Target Double-StrandedPolynucleotide> First Embodiment

In one embodiment thereof, the present invention provides a method forsite-specifically modifying a target double-stranded polynucleotide,provided with:

a step for mixing and incubating a target double-strandedpolynucleotide, a protein and a guide RNA, a step for having the proteinbind with the target double-stranded polynucleotide at a binding sitelocated upstream of a PAM sequence, and a step for obtaining a modifiedtarget double-stranded polynucleotide in a region determined bycomplementary binding between the guide RNA and the targetdouble-stranded polynucleotide; wherein,

the aforementioned target double-stranded polynucleotide has a PAMsequence composed of NG (wherein, N represents any base and G representsguanine),

the aforementioned protein is the protein indicated in the previoussection on the aforementioned <Cas9 Protein Recognizing Wide Range ofPAM Sequences>, and

the aforementioned guide RNA contains a polynucleotide composed of abase sequence complementary to a base sequence located 1 to 20 to 24bases upstream from the aforementioned PAM sequence in theaforementioned target double-stranded polynucleotide.

According to the method of the present embodiment, a targetdouble-stranded polynucleotide can be modified easily, rapidly andsite-specifically for a target sequence by using RNA-guided DNAendonuclease recognizing a wide range of PAM sequences.

In the present embodiment, the target double-stranded polynucleotide,protein and guide RNA are as indicated in the previous sections on <Cas9Protein Recognizing Wide Range of PMA Sequences> and <Method forSite-Specifically Modifying Target Double-Stranded Polynucleotide>.

The following provides a detailed explanation of the method forsite-specifically modifying a target double-stranded polynucleotide. Thesteps through site-specifically bind to a target double-strandedpolynucleotide are the same as in the previous section on <Method forSite-Specifically Cleaving Target Double-Stranded Polynucleotide>. Then,a target double-stranded polynucleotide that has been modified asnecessary in a region determined by complementary binding between theguide RNA and the target double-stranded polynucleotide is obtained.

In the present description, “modification” refers to a change in thebase sequence of a target double-stranded polynucleotide. Examplesthereof include cleavage of a target double-stranded polynucleotide,alteration of the base sequence of a target double-strandedpolynucleotide by inserting an exogenous sequence following cleavage (byphysical insertion or insertion by replicating through homology-directedrepair), and alteration of the base sequence of a target double-strandedpolynucleotide by non-homologous end-joining (NHEJ: rejoining the endsof DNA resulting from cleavage) following cleavage, as well as additionof functional protein or base sequence and the like.

Modification of a target double-stranded polynucleotide in the presentembodiment makes it possible to introduce a mutation into the targetdouble-stranded polynucleotide or disrupt or modify the function of thetarget double-stranded polynucleotide.

Second Embodiment

In the present embodiment, an expression step may be further providedprior to the incubation step in which the protein indicated in theprevious section on <Cas9 Protein Recognizing Wide Range of PAMSequences> and guide RNA are expressed using the previously describedCRISPR-Cas vector system.

In the expression step of the present embodiment, Cas9 protein and guideRNA are first expressed using the aforementioned CRISPR-Cas vectorsystem. The specific expression method is similar to the methodexemplified in the second embodiment in the previous section on <Methodfor Site-Specifically Modifying Target Double-Stranded Polynucleotide>.

<Method for Site-Specifically Modifying Target Double-StrandedPolynucleotide in Cells>

In one embodiment thereof, the present invention provides a method forsite-specifically modifying a target double-stranded polynucleotide incells, provided with:

a step for introducing the previously described CRISPR-Cas9 vectorsystem into a cell and expressing protein indicated in the previoussection on <Cas9 Protein Recognizing Wide Range of PAM Sequences> andguide RNA,

a step for having the aforementioned protein bind with theaforementioned target double-stranded polynucleotide at a binding sitelocated upstream of a PAM sequence, and

a step for obtaining a modified target double-stranded polynucleotide ina region determined by complementary binding between the aforementionedguide RNA and the aforementioned target double-stranded polynucleotide;wherein,

the aforementioned target double-stranded polynucleotide has a PAMsequence composed of NG (wherein, N represents any base and G representsguanine),

the aforementioned guide RNA contains a polynucleotide composed of abase sequence complementary to a base sequence located 1 to 20 to 24bases upstream from the aforementioned PAM sequence in theaforementioned target double-stranded polynucleotide.

In the expression step of the present embodiment, first, Cas9 proteinand guide RNA are expressed in a cell using the aforementionedCRISPR-Cas vector system.

Examples of organisms serving as the origin of the cells targeted forapplication of the method of the present embodiment include prokaryote,yeast, animal, plant, insect and the like. There are no particularlimitations on the aforementioned animals, and examples thereof include,but are not limited to, human, monkey, dog, cat, rabbit, swine, bovine,mouse, rat and the like. In addition, the type of organism serving asthe source of the cells can be arbitrarily selected according to thedesired type or objective of the target double-stranded polynucleotide.

Examples of animal-derived cells targeted for application of the methodof the present embodiment include, but are not limited to, germ cells(such as sperm or ova), somatic cells composing the body, stem cells,progenitor cells, cancer cells isolated from the body, cells isolatedfrom the body that are stably maintained outside the body as a result ofhaving become immortalized (cell line), and cells isolated from the bodyfor which the nuclei have been artificially replaced.

Examples of somatic cells composing the body include, but are notlimited to, cells harvested from arbitrary tissue such as the skin,kidneys, spleen, adrenals, liver, lungs, ovaries, pancreas, uterus,stomach, small intestine, large intestine, urinary bladder, prostategland, testes, thymus, muscle, connective tissue, bone, cartilage,vascular tissue, blood, heart, eyes, brain or neural tissue. Specificexamples of somatic cells include, but are not limited to, fibroblasts,bone marrow cells, immune cells (e.g., B lymphocytes, T lymphocytes,neutrophils, macrophages or monocytes etc.), erythrocytes, platelets,osteocytes, bone marrow cells, pericytes, dendritic cells,keratinocytes, adipocytes, mesenchymal cells, epithelial cells,epidermal cells, endothelial cells, intravascular endothelial cells,lymphatic endothelial cells, hepatocytes, pancreatic islet cells (e.g.,α cells, β cells, δ cells, ε cells or PP cells etc.), chondrocytes,cumulus cells, glia cells, nerve cells (neurons), oligodendrocytes,microglia cells, astrocytes, cardiomyocytes, esophageal cells, musclecells (e.g., smooth muscle cells or skeletal muscle cells etc.),melanocytes and mononuclear cells, and the like.

Stem cells refer to cells having both the ability to self-replicate aswell as the ability to differentiate into a plurality of other celllines. Examples of stem cells include, but are not limited to, embryonicstem cells (ES cells), embryonic tumor cells, embryonic germ stem cells,induced pluripotent stem cells (iPS cells), neural stem cells,hematopoietic stem cells, mesenchymal stem cells, hepatic stem cells,pancreatic stem cells, muscle stem cells, germ stem cells, intestinalstem cells, cancer stem cells and hair follicle stem cells, and thelike.

Cancer cells are cells derived from somatic cells that have acquiredreproductive integrity. Examples of the origins of cancer cells include,but are not limited to, breast cancer (e.g., invasive ductal carcinoma,non-invasive ductal carcinoma, inflammatory breast cancer etc.),prostate cancer (e.g., hormone-dependent prostate cancer orhormone-independent prostate cancer etc.), pancreatic cancer (e.g.,pancreatic ductal carcinoma etc.), gastric cancer (e.g., papillaryadenocarcinoma, mucinous carcinoma, adenosquamous carcinoma etc.), lungcancer (e.g., non-small cell lung cancer, small cell lung cancer,malignant mesothelioma etc.), colon cancer (e.g., gastrointestinalstromal tumor etc.), rectal cancer (e.g., gastrointestinal stromal tumoretc.), colorectal cancer (e.g., familial colorectal cancer, hereditarynon-polyposis colon cancer, gastrointestinal stromal tumor etc.), smallintestine cancer (e.g., non-Hodgkin's lymphoma, gastrointestinal stromaltumor etc.), esophageal cancer, duodenal cancer, tongue cancer,pharyngeal cancer (e.g., nasopharyngeal carcinoma, oropharyngealcarcinoma, hypopharyngeal carcinoma etc.), head and neck cancer,salivary gland cancer, brain tumor (e.g., pineal astrocytoma, pilocyticastrocytoma, diffuse astrocytoma, anaplastic astrocytoma etc.),schwannoma, liver cancer (e.g., primary liver cancer, extrahepatic bileduct cancer etc.), kidney cancer (e.g., renal cell carcinoma,transitional cell carcinoma of the renal pelvis and ureter etc.),gallbladder cancer, bile duct cancer, pancreatic cancer, endometrialcarcinoma, cervical cancer, ovarian cancer (e.g., epithelial ovariancancer, extragonadal germ cell tumor, ovarian germ cell tumor, ovarianlow malignant potential tumor etc.), bladder cancer, urethral cancer,skin cancer (e.g., intraocular (ocular) melanoma, Merkel cell carcinomaetc.), hemangioma, malignant lymphoma (e.g., reticulum cell sarcoma,lymphosarcoma, Hodgkin's etc.), melanoma (malignant melanoma), thyroidcancer (e.g., medullary thyroid cancer etc.), parathyroid cancer, nasalcancer, paranasal cancer, bone tumor (e.g., osteosarcoma, Ewing's tumor,uterine sarcoma, soft tissue sarcoma etc.), metastatic medulloblastoma,angiofibroma, protuberant dermatofibrosarcoma, retinal sarcoma, penilecancer, testicular tumor, pediatric solid tumor (e.g., Wilms tumor orpediatric kidney tumor etc.), Kaposi's sarcoma, AIDS-induced Kaposi'ssarcoma, maxillary sinus tumor, fibrous histiocytoma, leiomyosarcoma,rhabdomyosarcoma, chronic myeloproliferative disease and leukemia (e.g.,acute myelogenous leukemia, acute lymphoblastic leukemia etc.).

Cell lines refer to cells that have acquired reproductive integritythrough artificial manipulation ex vivo. Examples of cell lines include,but are not limited to, HCT116, Huh7, HEK293 (human embryonic kidneycells), HeLa (human cervical cancer cell line), HepG2 (human livercancer cell line), UT7/TPO (human leukemia cell line), CHO (Chinesehamster ovary cell line), MDCK, MDBK, BHK, C-33A, HT-29, AE-1, 3D9,NsO/1, Jurkat, NIH3T3, PC12, S2, Sf9, Sf21, High Five and Vero.

Introduction of the CRISPR-Cas vector system into cells can be carriedout using a method suitable for the viable cells used, and examplesthereof include electroporation method, heat shock method, calciumphosphate method, lipofection method, DEAE dextran method,microinjection method, particle gun method, methods using viruses, andmethods using commercially available transfection reagents such asFuGENE (registered trade mark) 6 Transfection Reagent (manufactured byRoche), Lipofectamine 2000 Reagent (manufactured by Invitrogen Corp.),Lipofectamine LTX Reagent (manufactured by Invitrogen Corp.) orLipofectamine 3000 Reagent (manufactured by Invitrogen Corp.).

Then, the modification step is the same as the methods indicated in thefirst embodiment in the previous section on

<Method for Site-Specifically Modifying Target Double-StrandedPolynucleotide>.

Modification of a target double-stranded polynucleotide in the presentembodiment makes it possible to obtain cells in which a mutation hasbeen introduced into the target double-stranded polynucleotide or thefunction of the target double-stranded polynucleotide has been disruptedand modified.

When an embodiment having no endonuclease activity (e.g., embodiment 5)is used as the mutant Cas9 protein of the present invention, the proteincan bind to the aforementioned target double-stranded polynucleotide ata binding site located upstream of the PAM sequence but cannot remainthere to cleave the double-stranded polynucleotide. Therefore, forexample, when a labeled protein such as a fluorescent protein (e.g.,GFP) is fused to the protein, the labeled protein can be bound to thetarget double-stranded polynucleotide via the guide RNA-mutant Cas9protein. By appropriately selecting a substance to be bound to themutant Cas9 protein, various functions can be imparted to the targetdouble-stranded polynucleotide.

Furthermore, a transcriptional regulatory protein or domain can belinked to the N-terminal or C-terminal of the mutant Cas9 protein or aprotein obtained by partly or entirely deleting cleavage enzyme activityfrom the mutant Cas9. Examples of the transcriptional regulator ordomain thereof include transcriptional activator or domain thereof(e.g., VP64, NF-κB p65) and transcription silencer or domain thereof(e.g., heterochromatin protein 1 (HP1)) and transcription inhibitoryfactor or domain thereof (e.g., Kruppel associated box (KRAB), ERFrepressor domain (ERD), mSin3A interacting domain (SID)).

Enzymes that modify the methylation state of DNA (e.g., DNAmethyltransferase (DNMT), TET) and enzymes that modify histone subunits(e.g., histone acetyltransferase (HAT), histone deacetylase (HDAC),histone methyltransferase, histone demethylase) can also be linked.

<Gene Therapy>

In one embodiment thereof, the present invention provides a method andcomposition for gene therapy by carrying out genome editing. In contrastto previously known methods for targeted gene recombination, the methodof the present embodiment can be carried out efficiently andinexpensively and can be applied to any cell or living organism. Anarbitrary segment of a double-stranded nucleic acid of a cell or livingorganism can be modified by the gene therapy method of the presentembodiment. The gene therapy method of the present embodiment utilizesboth homologous and non-homologous recombination processes present inall cells.

In the present description, the term “genome editing” refers to a novelgene modification technology for carrying out a specific gene disruptionor knock-in of a reporter gene by carrying out targeted recombination ortargeted mutation using a technology such as the CRISPR/Cas9 system ortranscription activator-like effector nucleases (TALEN).

In addition, in one embodiment thereof, the present invention provides agene therapy method for carrying out targeted DNA insertion or targetedDNA deletion. This gene therapy method includes a step for transforminga cell using a nucleic acid construct containing donor DNA. The schemerelating to DNA insertion or DNA deletion after cleaving a target genecan be determined by a person with ordinary skill in the art inaccordance with a known method.

In addition, in one embodiment thereof, the present invention provides agene therapy method for carrying out gene manipulation at a specificgenetic locus using both somatic cells and germ cells.

In addition, in one embodiment thereof, the present invention provides agene therapy method for disrupting a gene in a somatic cell. Here, thegene expresses a product harmful to cells or living organisms byover-expressing a substance harmful to cells or living organisms. Thistype of gene is over-expressed in one or more cell types generated in adisease. Disruption of the aforementioned over-expressed gene by thegene therapy method of the present embodiment is able to bring about amore favorable state of health in an individual suffering from a diseaseattributable to the aforementioned over-expressed gene. Namely,therapeutic effects are manifested as a result of the gene beingdisrupted in only a very small proportion of cells, thereby leading to areduction in the expression level thereof.

In addition, in one embodiment thereof, the present invention provides agene therapy method for disrupting a gene in a germ cell. Cells in whicha specific gene has been disrupted can be used to create livingorganisms that do not have the function of a specific gene. A gene canbe completely knocked out in cells in which the aforementioned gene hasbeen disrupted. This functional deficit in a specific cell can have atherapeutic effect.

In addition, in one embodiment thereof, the present invention provides agene therapy method for inserting a donor DNA encoding a gene product.This gene product has a therapeutic effect in the case of having beenconstitutively expressed. An example of such a method consists ofinserting donor DNA encoding an active promoter and insulin gene into anindividual (patient) suffering from diabetes in order to induceinsertion of the donor DNA in an individual group of pancreas cells.Next, the aforementioned individual group of pancreas cells containingthe aforementioned donor DNA produces insulin making it possible totreat the diabetes patient. Moreover, a drug-related gene product can bemade to be produced by inserting the aforementioned donor DNA into aplant. A gene of a protein product (such as insulin, lipase orhemoglobin) is inserted into the plant along with a control element(constitutively activated promoter or inducible promoter) to enable alarge amount of a pharmaceutical to be produced in the plant. Next, thisprotein product is isolated from the plant.

Transgenic plants or transgenic animals can be produced by methods usingnucleic acid transfer technology (McCreath, K. J. et al. (2000), Nature405: 1066-1069; Polejaeva, I. A. et al. (2000), Nature 407: 86-90). Atissue type-specific vector or cell type-specific vector can be used toprovide gene expression only in selected cells.

In addition, in the case of using the aforementioned method in germcells, cells can be produced having a designed genetic alteration byinserting donor DNA into a target gene and allowing all of thesubsequent cells to undergo cell division.

Examples of application targets of the gene therapy method of thepresent embodiment include, but are not limited to, any livingorganisms, cultured cells, cultured tissue, cultured nuclei (includingcells, tissue or nuclei able to be used to regenerate a living organismin cultured cells, cultured tissue or intact cultured nuclei) andgametes (e.g., ova or sperm in various stages of development).

Examples of the origins of cells targeted for application of the genetherapy method of the present embodiment include, but are not limitedto, any living organisms (such as insect, fungi, rodent, bovine, sheep,goat, chicken and other agriculturally important animal along with othermammals (e.g., dog, cat or human, although not limited thereto)).

Moreover, the gene therapy method of the present embodiment can be usedin plants. There are no particular limitations on those plants targetedfor application of the gene therapy method of the present embodiment,and the gene therapy method of the present embodiment can be applied tovarious arbitrary plant species (e.g., monocotyledons or dicotyledonsetc.).

While the present invention is explained in more detail in the followingby referring to Examples, they do not limit the scope of the presentinvention.

EXAMPLE Example 1 1. Preparation of Wild-Type and Mutant SpCas9 (1)Construct Design

Wild-type or mutant SpCas9 gene in which codons had been optimized bygene synthesis was incorporated in pET vector (Novagen). Moreover, a TEVrecognition sequence was added between His tag and the SpCas9 gene. Thedesign of the construct was such that six consecutive histidine residues(His tag) were linked followed by the addition of the TEV proteaserecognition site to the N-terminal of the Cas9 expressed by thecompleted construct.

The base sequences of the SpCas9 genes used are as follows.

WT: base sequence of wild-type SpCas9: SEQ ID NO: 2m0: base sequence of mutant SpCas9 gene (R1335A): SEQ ID NO: 3m4: base sequence of mutant SpCas9 gene (R1335A/G1218R): SEQ ID NO: 4m18: base sequence of mutant SpCas9 gene (R1335A/G1218R/T1337R): SEQ IDNO: 5m19: base sequence of mutant SpCas9 gene (R1335A/G1218R/T1337R/L1111R):SEQ ID NO: 6m20: base sequence of mutant SpCas9 gene(R1335A/G1218R/T1337R/L1111R/D1332R): SEQ ID NO: 7m21: base sequence of mutant SpCas9 gene(R1335A/G1218R/T1337R/L1111R/D1332R/A1322R): SEQ ID NO: 8m22: base sequence of mutant SpCas9 gene(R1335A/G1218R/T1337R/L1111R/D1332R/A1322R/D1284R/A1285R): SEQ ID NO: 9m23: base sequence of mutant SpCas9 gene(R1335A/G1218R/L1111R/D1332R/A1322R): SEQ ID NO: 10m24: base sequence of mutant SpCas9 gene(R1335A/G1218R/L1111R/D1332R/A1322R/D1284R/A1285R): SEQ ID NO: 11m25: base sequence of mutant SpCas9 gene(R1335A/G1218R/T1337R/L1111R/A1322R): SEQ ID NO: 12m26: base sequence of mutant SpCas9 gene (R1335A/G1218R/L1111R/A1322R):SEQ ID NO: 13m29: base sequence of mutant SpCas9 gene (R1335A/G1218R/L1111R): SEQ IDNO: 14m32: base sequence of mutant SpCas9 gene(R1335A/G1218R/T1337R/L1111R/A1322R/E1219M): SEQ ID NO: 15m33: base sequence of mutant SpCas9 gene(R1335A/G1218R/T1337R/L1111R/A1322R/E1219F): SEQ ID NO: 16m34: base sequence of mutant SpCas9 gene(R1335A/G1218R/T1337R/L1111R/A1322R/E1219W): SEQ ID NO: 17m43: base sequence of mutant SpCas9 gene(R1335A/G1218R/T1337R/L1111R/A1322R/E1219F/D1135V): SEQ ID NO: 18m61: base sequence of mutant SpCas9 gene(R1335I/G1218R/T1337R/L1111R/A1322R/E1219F/D1135V): base sequence of m43(SEQ ID NO: 18) in which the 4003- to 4005-position gcc is converted toatc.m62: base sequence of mutant SpCas9 gene(R1335L/G1218R/T1337R/L1111R/A1322R/E1219F/D1135V): base sequence of m43(SEQ ID NO: 18) in which the 4003- to 4005-position gcc is converted toctg.m63: base sequence of mutant SpCas9 gene(R1335M/G1218R/T1337R/L1111R/A1322R/E1219F/D1135V): base sequence of m43(SEQ ID NO: 18) in which the 4003- to 4005-position gcc is converted toatg.m64: base sequence of mutant SpCas9 gene(R1335F/G1218R/T1337R/L1111R/A1322R/E1219F/D1135V): base sequence of m43(SEQ ID NO: 18) in which the 4003- to 4005-position gcc is converted tottt.m65: base sequence of mutant SpCas9 gene(R1335T/G1218R/T1337R/L1111R/A1322R/E1219F/D1135V): base sequence of m43(SEQ ID NO: 18) in which the 4003- to 4005-position gcc is converted toacc.m66: base sequence of mutant SpCas9 gene(R1335V/G1218R/T1337R/L1111R/A1322R/E1219F/D1135V): base sequence of m43(SEQ ID NO: 18) in which the 4003- to 4005-position gcc is converted togtg.(2) Expression in Escherichia coli

The resulting vectors were used to transform Escherichia coli strainrosetta 2 (DE3). Subsequently, the E. coli were cultured in LB mediumcontaining 20 μg/ml of kanamycin and 20 μg/ml of chloramphenicol. Afterhaving cultured to OD=0.8, an expression inducing agent in the form ofisopropyl-β-D-1-thiogalactopyranoside (IPTG) (final concentration: 1 mM)was added followed by culturing for 4 hours at 37° C. Followingculturing, the E. coli were recovered by centrifugation (5,000 g, 10minutes).

(3) Purification of Wild-Type and Mutant SpCas9

The bacterial cells recovered in (2) were suspended in a Buffer A andsubjected to ultrasonication. Supernatant was recovered bycentrifugation (25,000 g, 30 minutes) followed by mixing with Ni-NTASuperflow Resin (Qiagen Inc.) equilibrated with a Buffer A and gentlyinverting for 1 hour. After recovering the effluent fraction, the columnwas washed with the Buffer A in an amount equal to four times the columnvolume and a high salt concentration Buffer B in an amount equal to twotimes the column volume.

Then, after again washing with the Buffer A using an amount equal totwice the column volume, the target protein was eluted with a highimidazole concentration Buffer C in an amount equal to five times thecolumn volume.

Then, the crudely purified sample was charged into HiTrapSP (GEHealthcare). After washing with a mixture of 92.5% Buffer D (0 M NaCl)and 7.5% Buffer F (2 M NaCl) in an amount equal to five times the columnvolume, the target protein was eluted by applying a linear gradient inwhich the concentration of Buffer E increased from 10% to 50% (NaClconcentration increased from 200 mM to 1 M).

The compositions of Buffers A to E are shown below.

Buffer A: 20 mM Tris-HCl, pH 8.0, 300 mM NaCl, 20 mM imidazoleBuffer B: 20 mM Tris-HCl, pH 8.0, 1000 mM NaCl, 20 mM imidazoleBuffer C: 20 mM Tris-HCl, pH 8.0, 300 mM NaCl, 300 mM imidazole

Buffer D: 20 mM Tris-HCl, pH 8.0 Buffer E: 20 mM Tris-HCl, pH 8.0, 2000mM NaCl 2. Preparation of Guide RNA

A vector inserted with the target guide RNA sequence

(ggaaauuaggugcgcuuggcguuuuagagcuagaaauagcaaguuaaaauaaggcuaguccguuaucaacuugaaaaagug; SEQ ID NO: 19)was prepared. The underlined part shows a 20 base guide sequence and therest corresponds to a scaffold part (stem-loop 2). A T7 promotersequence was added upstream from the guide RNA sequence followed byincorporating a linearized pUC119 vector (Takara Corp.). Template DNAfor an in vitro transcription reaction was produced using PCR based onthe resulting vector. An in vitro transcription reaction was carried outby T7 RNA polymerase for 4 hours at 37° C. using this DNA template.After adding an equal volume of phenol-chloroform to the reactionsolution containing the transcription product and mixing, the solutionwas centrifuged at 20° C. (10,000 g, 2 minutes) to recover thesupernatant. 1/10th volume of 3 M sodium acetate and 2.5 volumes of 100%ethanol were added to the supernatant followed by centrifuging at 4° C.(10,000 g, 3 minutes) to precipitate the transcription product. Thesupernatant was discarded followed by adding 70% ethanol, centrifugingat 4° C. (10,000 g, 3 minutes) and again discarding the supernatant.After allowing the precipitate to air-dry, the precipitate wasre-suspended in TBE buffer and purified by 7 M urea-denatured 10% PAGE.The band located at the molecular weight of the target RNA was cut outand the RNA was extracted with the Elutrap electroelution system (GEHealthcare Inc.). Subsequently, the eluted RNA was passed through aPD-10 column (GE Healthcare Inc.) and the buffer solution was replacedwith Buffer H (10 mM Tris-HCl (pH 8.0), 150 mM NaCl).

3. Plasmid DNA Cleavage Activity Measurement Test

Vectors inserted with the target DNA sequence and PAM sequence wereprepared for use in a DNA cleavage activity measurement test. PAMsequences 1 to 4 were each added to the target DNA sequence andincorporated in a linearized pUC119 vector. The target DNA sequence andPAM sequences 1 to 4 are shown in Table 1.

TABLE 1 base sequence SEQ ID NO: target DNA 5′-GGAAATTAGG SEQ ID NO: 20TGCGCTTGGC-3′ PAM sequence 1 5′-TGT-3′ PAM sequence 2 5′-TGG-3′PAM sequence 3 5′-TGNA-3′ PAM sequence 4 5′-TGN-3′

Escherichia coli strain Machi (Life Technologies) was transformed usingthe prepared vectors followed by culturing at 37° C. in LB mediumcontaining 20 μg/ml of ampicillin.

Following culturing, the bacterial cells were recovered bycentrifugation (8,000 g, 1 minute) and the plasmid DNA was purifiedusing the QIAprep Spin Miniprep Kit (QIAGEN).

A cleavage experiment was carried out using the purified target plasmidDNA containing PAM sequence. The plasmid DNA was linearized into asingle strand with restriction enzyme. When the wild-type or mutantSpCas9 was cleaved from the target DNA sequence in this linearized DNA,approximately 1000 bp and 2000 bp cleavage products were obtained. Asthe buffer for cleavage, cleavage buffer B with the followingcomposition was used.

composition of B(×10)

200 mM HEPES 7.5

1000 mM KCl

50% glycerol

10 mM DTT

5 mM EDTA

20 mM MgCl₂

The samples were electrophoresed using agarose gel having aconcentration of 1% following the reaction, and bands corresponding tothe cleavage products were confirmed. The results are shown in FIGS. 1Ato D. In the Figure, “Substrate” indicates the substrate while “Product”indicates the cleavage products. The PAM sequence and the reactionconditions are shown in the Figures.

In contrast to the target plasmid DNA having been cleaved as a result ofrecognizing only G for the third base of the PAM sequence in the case ofthe wild-type SpCas9, in the case of the mutant SpCas9, the targetplasmid DNA could be cleaved as a result of recognizing PAM sequences inwhich the third base was other than G.

Accordingly, in contrast to recognizing “NGG” for the PAM sequence inthe case of the wild-type SpCas9, the PAM sequence “NG” was confirmed tobe recognized in the case of the mutant SpCas9.

Based on the above results, mutant SpCas9 was determined to be able torecognize a wide range of PAM sequences and site-specifically cleave atarget double-stranded polynucleotide for a target sequence both easilyand rapidly.

Example 2

Plasmid DNA Cleavage Activity Measurement Test was performed in the samemanner as in Example 1 and using the mutant SpCas9(m43) prepared inExample 1. The results are shown in FIG. 2.

In contrast to the target plasmid having been cleaved as a result ofrecognizing only G for the third base of the PAM sequence in the case ofthe wild-type SpCas9, in the case of the mutant SpCas9, the targetplasmid DNA could be cleaved as a result of recognizing PAM sequences inwhich the third base was other than G.

Accordingly, in contrast to recognizing “NGG” for the PAM sequence inthe case of the wild-type SpCas9, the PAM sequence “NG” was confirmed tobe recognized in the case of the mutant SpCas9.

Example 3

Plasmid DNA Cleavage Activity Measurement Test was performed in the samemanner as in Example 1 and using the mutant SpCas9 (m43, m61-m66)prepared in Example 1. For detection of a cleavage product, MultiNAcapillary electrophoresis apparatus (Shimadzu Corporation) was used. Asthe PAM sequence, 5′-TGC-3′ (PAM sequence 4) was used. The cleavageexperiment was performed for 0.5 minute (0.5 m) and 2 minutes (2 m). Theresults are shown in FIG. 3. Superior DNA cleavage activity wasconfirmed in m61, m63, m65 and m66.

Example 4

Plasmid DNA Cleavage Activity Measurement Test was performed in the samemanner as in Example 1 and using the mutant SpCas9 (m43, m61, m63 andm66) prepared in Example 1. The cleavage experiment was performed for0.5 minute (0.5 m) and 2 minutes (2 m). The results are shown in FIG. 4.

In contrast to the target plasmid having been cleaved as a result ofrecognizing only G for the third base of the PAM sequence in the case ofthe wild-type SpCas9, in the case of the mutant SpCas9, the targetplasmid DNA could be cleaved as a result of recognizing PAM sequences inwhich the third base was other than G. It was confirmed that m61, m63and m66, particularly m63 and m66, could cleave DNA with high efficiencyeven when the PAM sequences of TGA and TGC, which showed low efficiencyin m43, were used.

Example 5

Plasmid DNA Cleavage Activity Measurement Test was performed in the samemanner as in Example 1 and using wild-type SpCas9 and mutant SpCas9(WT,m43) prepared in Example 1 and the following mutant SpCas9 prepared inthe same manner as in Example 1. The cleavage experiment was performedover time (0, 0.5, 1, 2, 5 min). The results are shown in FIG. 5. Inm43, rising of cleavage activity which is comparable to that in WT wasconfirmed.

base sequence of mutant SpCas9 gene(R1335A/G1218R/T1337R/L1111R/A1322R/D1135V): base sequence of m25 (SEQID NO: 12) in which the 3403- to 3405-position gac is converted to gtt.

INDUSTRIAL APPLICABILITY

According to the present invention, a Cas9 protein can be obtained thatrecognizes a wide range of PAM sequences while retaining bindingstrength with a target double-stranded polynucleotide and furtherretaining endonuclease activity. In addition, a simple and rapidsite-specific genome editing technology for a target sequence can beprovided that uses the aforementioned Cas9 protein.

This application is based on patent application No. 2017-108556 filed inJapan (filing date: May 31, 2017), the contents of which are encompassedin full herein.

1. A polynucleotide encoding a protein consisting of a sequencecomprising the amino acid sequence shown in SEQ ID NO: 1 which hasmutations at the 1219-position, the 1322-position, the 1335-position,and at at least three positions selected from the group consisting ofthe 1111-position, the 1135-position, the 1218-position, and the1337-position of the amino acid sequence and which binds guide RNA,wherein the mutation at the 1219-position is a substitution of glutamicacid to one amino acid selected from the group consisting ofphenylalanine, methionine, and tryptophan, the mutation at the1322-position is a substitution of alanine to arginine, the mutation atthe 1335-position is a substitution of arginine to one amino acidselected from the group consisting of alanine, isoleucine, leucine,methionine, phenylalanine, valine, and threonine, the mutation at the1111-position is a substitution of leucine to arginine, the mutation atthe 1135-position is a substitution of aspartic acid to valine, themutation at the 1218-position is a substitution of glycine to arginine,and the mutation at the 1337-position is a substitution of threonine toarginine.
 2. The polynucleotide according to claim 1, wherein the1335-position arginine is substituted with alanine, isoleucine,methionine, threonine or valine.
 3. The polynucleotide according toclaim 1, wherein the mutation at 1219-position is a substitution ofglutamic acid to phenylalanine.
 4. The polynucleotide according to claim1, wherein the protein has RNA-guided DNA endonuclease activity.
 5. Thepolynucleotide according to claim 1, wherein the protein consisting of asequence comprising the amino acid sequence shown in SEQ ID NO: 1further has a mutation that partly or entirely deletes nucleaseactivity.
 6. The polynucleotide according to claim 5, wherein themutation that partly or entirely deletes nuclease activity is a mutationat, in the amino acid sequence shown in SEQ ID NO: 1, at least one siteselected from the group consisting of (i) the 10-position, the762-position, the 839-position, the 983-position and the 986-position ora position corresponding thereto, and/or (ii) a site selected from thegroup consisting of the 840-position and the 863-position or a positioncorresponding thereto.
 7. The polynucleotide according to claim 6,wherein the 10-position aspartic acid is substituted by alanine orasparagine; or the 840-position histidine is substituted by alanine,asparagine or tyrosine.
 8. The polynucleotide according to claim 5,wherein a transcriptional regulator protein or domain is linked.
 9. Thepolynucleotide according to claim 8, wherein the transcriptionalregulator is a transcription activation factor.
 10. The polynucleotideaccording to claim 8, wherein the transcriptional regulator is atranscription silencer or a transcription inhibitory factor.